v3.26.1
Fair Value Measurement - Financial Instruments Carried at Fair Value (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Assets:    
Fixed-maturity securities, available for sale $ 6,875 $ 6,369
Fixed-maturity securities, trading 127 124
Short-term investments, at fair value 768 903
Other invested assets fair value 3 3
Funds withheld, at fair value 296 0
Total assets carried at fair value 8,416 7,912
FG VIEs’ assets, measurement input   167
Other assets 180 174
Liabilities:    
Other liabilities. fair value disclosure 26 21
Total liabilities carried at fair value 178 218
Variable Interest Entity, Primary Beneficiary    
Assets:    
Total assets carried at fair value 167 172
Liabilities:    
Total liabilities carried at fair value 152 197
Obligations of state and political subdivisions    
Assets:    
Fixed-maturity securities, available for sale 1,744 1,769
U.S. government and agencies    
Assets:    
Fixed-maturity securities, available for sale 52 52
Corporate securities    
Assets:    
Fixed-maturity securities, available for sale 3,350 2,952
RMBS    
Assets:    
Fixed-maturity securities, available for sale 624 615
CMBS    
Assets:    
Fixed-maturity securities, available for sale 272 198
Asset-backed securities    
Assets:    
Fixed-maturity securities, available for sale 615 665
Non-U.S. government securities    
Assets:    
Fixed-maturity securities, available for sale 218 118
Level 1    
Assets:    
Fixed-maturity securities, available for sale 0 0
Fixed-maturity securities, trading 0 0
Short-term investments, at fair value 767 898
Other invested assets fair value 0 0
Funds withheld, at fair value 0  
Total assets carried at fair value 858 994
FG VIEs’ assets, measurement input   0
Other assets 81 81
Liabilities:    
Other liabilities. fair value disclosure 0 0
Total liabilities carried at fair value 0 0
Level 1 | Variable Interest Entity, Primary Beneficiary    
Assets:    
Total assets carried at fair value 10 15
Liabilities:    
Total liabilities carried at fair value 0 0
Level 1 | Obligations of state and political subdivisions    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 1 | U.S. government and agencies    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 1 | Corporate securities    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 1 | RMBS    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 1 | CMBS    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 1 | Asset-backed securities    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 1 | Non-U.S. government securities    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 2    
Assets:    
Fixed-maturity securities, available for sale 6,134 5,536
Fixed-maturity securities, trading 119 120
Short-term investments, at fair value 1 5
Other invested assets fair value 0 0
Funds withheld, at fair value 0  
Total assets carried at fair value 6,331 5,733
FG VIEs’ assets, measurement input   0
Other assets 66 65
Liabilities:    
Other liabilities. fair value disclosure 5 0
Total liabilities carried at fair value 5 0
Level 2 | Variable Interest Entity, Primary Beneficiary    
Assets:    
Total assets carried at fair value 11 7
Liabilities:    
Total liabilities carried at fair value 0 0
Level 2 | Obligations of state and political subdivisions    
Assets:    
Fixed-maturity securities, available for sale 1,734 1,759
Level 2 | U.S. government and agencies    
Assets:    
Fixed-maturity securities, available for sale 52 52
Level 2 | Corporate securities    
Assets:    
Fixed-maturity securities, available for sale 3,188 2,784
Level 2 | RMBS    
Assets:    
Fixed-maturity securities, available for sale 484 471
Level 2 | CMBS    
Assets:    
Fixed-maturity securities, available for sale 272 198
Level 2 | Asset-backed securities    
Assets:    
Fixed-maturity securities, available for sale 186 154
Level 2 | Non-U.S. government securities    
Assets:    
Fixed-maturity securities, available for sale 218 118
Level 3    
Assets:    
Fixed-maturity securities, available for sale 741 833
Fixed-maturity securities, trading 8 4
Short-term investments, at fair value 0 0
Other invested assets fair value 3 3
Funds withheld, at fair value 296  
Total assets carried at fair value 1,227 1,185
FG VIEs’ assets, measurement input   167
Other assets 33 28
Liabilities:    
Other liabilities. fair value disclosure 21 21
Total liabilities carried at fair value 173 218
Level 3 | Variable Interest Entity, Primary Beneficiary    
Assets:    
Total assets carried at fair value 146 150
Liabilities:    
Total liabilities carried at fair value 152 197
Level 3 | Obligations of state and political subdivisions    
Assets:    
Fixed-maturity securities, available for sale 10 10
Level 3 | U.S. government and agencies    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 3 | Corporate securities    
Assets:    
Fixed-maturity securities, available for sale 162 168
Level 3 | RMBS    
Assets:    
Fixed-maturity securities, available for sale 140 144
Level 3 | CMBS    
Assets:    
Fixed-maturity securities, available for sale 0 0
Level 3 | Asset-backed securities    
Assets:    
Fixed-maturity securities, available for sale 429 511
Level 3 | Non-U.S. government securities    
Assets:    
Fixed-maturity securities, available for sale $ 0 $ 0